Build Details of a Revamped Stroker

Muscle Mouse

Jake Amatisto Jan 31, 2014 0 Comment(s)
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In this month's engine build, we resurrect an old bracket car combo with modern cylinder heads and a single plane intake manifold from Racing Head Service, an aggressive hydraulic roller camshaft and valvetrain from COMP Cams, and an internally balanced crankshaft from Scat Enterprises. We're also running a F.A.S.T. EZ-EFI setup on this engine, which we are very interested in watching how the self-learning works on a combination like this.

With these readily available components and a freshened short-block from Vrbancic Brothers Racing, we aimed to make 450-plus horsepower on pump fuel.

Rhs 2/18

Of course, in order to put together a reliable, high-powered pump gas mill, we had one of the most experienced engine builders in Southern California assemble the pieces and carefully blueprint the combination to make the power we're after, but to also make it last on the street. Vrbancic Brothers Racing has been in business of making horsepower for the past thirty years and judging by the walls in their office, their customer's all have successful speed machines.

Taking what we thought to be a 391 stroker we had built a decade ago, Bob and George revealed to us that the engine is in fact slightly smaller than we expected. With a 4.030 bore and a crank with a 3.80-inch stroke (the most common is 3.75-inch), it adds up to be over 387 cubic inches, 387.7 to be exact; so call it a 388ci.

QUICK SPECS

  • Scat crank & rods: 3.80 stroke, 6-inch rods
  • JE Pistons: -7cc dished for 9.7:1 compression
  • Total Seal rings & bearings
  • Short block freshened by Vrbancic Brothers Racing
  • RHS Pro Action heads: 200cc runner, 64cc chamber
  • COMP Cams hydraulic roller: 0.540/0.562 lift, 242/248 duration at 0.050
  • COMP Cams Magnum roller rockers: 1.5 ratio
  • RHS single-plane intake
  • FAST EZ-EFI
  • Pertronix ignition & wires

Scat 3/18

1. Before we arrived at Vrbancic Brothers Racing in Ontario, California, the short-block had just been freshened up with new rings, bearings and a Scat crankshaft. The crank was actually offset ground, giving it a 3.80-inch stroke.

Melling Oil 4/18

2. Before dropping on the oil pan, Vrbancic replaced the oil pump with a Melling high-volume piece and bolted up the matching oil pump pickup from Hamburger’s Performance.

Hamburgers Deep Sump Oil 5/18

3. The deep sump oil pan from Hamburger’s has a built-in windage tray.

Hamburgers Oil Pan Trap Door Baffle 6/18

4. The deep sump oil pan from Hamburger’s also uses a trap door baffle system to keep the pickup covered in oil at high speeds.

Comp Cams Valve 7/18

5. The RHS Pro Action 200cc heads were set up with COMP Cams valve springs needed to match the hydraulic roller camshaft we chose. This combo will likely make peak power somewhere in the 5,500-6,000 rpm range.

Je 8/18

6. Forged JE Pistons provide a 9.7:1 compression ratio.

Fast Ez 9/18

7. F.A.S.T.’s EZ-EFI was chosen to control the fuel on this 388 stroker. We’ve already tested a couple engines with this setup and were thoroughly pleased with how it operates. We’ll go more into how this system works when we test it on Vrbancic’s dyno next month.

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